Uncertainty reduces rejections of unfair offers in the ultimatum game.

Considerable Ultimatum Game studies suggest that individuals tend to reject unfair offers even at the cost of personal financial loss. Different from prior studies in which the ultimatum game allocations are often certain (e.g., $2: $8), the current research examines whether uncertain allocations (e.g., $1–$3: $7–$9) alter the rejections in two incentive compatible studies. That is, whether unfair offers influence rejection rates in ultimatum game decisions. Study 1 showed that decision makers are generally less likely to reject unfair offers when they are uncertain (between $1 and $3) rather than certain ($2). Study 2 replicated the effect and further revealed a boundary: when the range of the uncertain offer includes zero such that there is a possibility of receiving nothing, decision makers exhibited similar rejection rates for uncertain and certain unfair offers. [ABSTRACT FROM AUTHOR]